Electrical system for doctor blade control in paper making machines



E. HAPP 7,79

ELECTRICAL SYSTEM FOR DOCTOR BLADE CONTROL IN PAPER MAKING MACHINESMarch 18, 1947.

- 2 Sheets-Sheet 1' Filed March 18, 1943 3nventor: ups-Mm Edna in, Ie WPM Z is Gttorneg,

March 18, 1947. E. HAPP ELECTRICAL SYSTEM FOR DOCTOR BLADE CONTROL INPAPER MAKING MACHINES 2 Sheets-Sheet 2 'Filed March 18, 1943 3nventor;

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Patented Mar. 18, 1947 ELECTRICAL SYSTEM FOR DOCTOR BLADE CONTROL INPAPER MAKING MACHINES Edwin Lewis Happ, Brevard, N. 0., asslgnor toEcusta Paper Corporation, a corporation of Delaware Application March18, 1943, Serial No. 479,635

2 Claims.

This invention relates to paper making machines and has to do moreparticularly with the operating control of the doctor blade of suchmachines.

In paper making machines there is usually cooperatively associated withthe dryer cylinder, a bladed device known in the art as a doctor. Theblade member of this device is usually maintained in edge contact withthe circumferential face of the rotating dryer cylinder so as to keepthe latter clean by removing therefrom dust, fibers and other foreignmatter or broken paper that might adhere thereto.

To prevent scratching or scoring the surface annularly of the dryercylinder provision is made for constantly reciprocating the doctor bladelongitudinally during the time the cylinder is rotating, but unlessreciprocation of the doctor blade is stopped when rotation of thecylinder ceases the edge of the blade is liable to mar the face of thecylinder with detrimental scratches or scores transversely thereof.

Attempts have been made by the use of various mechanical contrivancesfor a timed starting and stopping of reciprocation of the doctor bladeupon the starting and stopping of dryer cylinder rotation. Suchmechanisms are not only more or less intricate and expensive to produceand maintain in working condition, but it has been found difficult (ifat all possible) to automatically start and stop reciprocatory operationof the doctor blade simultaneously with the starting and stopping ofrotation of the dryer cylinder or at least at the proper time to preventmarring of the surface of the dryer cylinder.

The present invention has been brought about for the attainment of asimplified and economical yet better and more positive and accuratelytimed control of the doctor blade reciprocation. This is accomplished bythe utilization of an instantly operative electrical system inelimination of mechanical complication but in a direct and practical,cooperative controlling relation between the driving means of the dryercylinder and the motive means of the doctor device.

A practical and non-limiting exemplification of the present invention isset forth in the following description in conjunction with theaccompanying illustrative drawings, in which,

Fig. 1 is a view, more or less fragmentary and schematic, showing adryer cylinder, finished paper roll and intermediate idler guide roll ofa conventional paper making machine in end elevation, and a portion ofthe machine frame broon the roll l5.

ken away to show the doctor blade in edge contact with thedryer'cylinder;

Fig. 2 is a more or less fragmentary view, at a right angle to that ofFig. 1, of the machine in the region of the dryer cylinder and showingin more detail the doctor device and its operating means, together withthe electrical control provision for said operating means;

Fig. 3 is top plan view of the electrical switch unit with the coverremoved from the housing; and

Fig. 4 is a section on the line 44 of Fig. 3, with the cover in place onthe housing.

Referring now to the drawings in detail, the numeral designates theportion of the main frame of the machine on which the dryer cylinder His rotatably mounted, as at l2. The paper web 13 as preformed in themachine travels over the cylinder II and is thus dried in the usualmanner, whence it passes under an idler guide roller l4 and is thentaken up on the finished paper roll l (see Fig. 1). In some machines thedried paper is passed through a calendering medium or otherwise treatedbefore it is wound Such treatment of the paper after leaving the dryercylinder, however, has

nothing to do with the present invention. Hence, no detailed descriptionor illustration of the same is here given.

For purposes of conventional illustration the dryer cylinder H (see Fig.2) is provided with a master gear 16 on its shaft. This gear I6 is inmesh with an idler pinion I! which, in turn, is in mesh with a drivingpinion l8 fixed on a power shaft IS. The shaft I9 is journalled at oneend in a bearing 20 on the adjacent main frame member Ill, and at itsopposite end is journalled, as at 2!, on an outer auxiliary frame member22. As shown, the power shaft I9 is provided with a driving pulley ofthe conical type 23, which, in practice, is belted to a similar butreversely disposed driving pulley (not shown) at the source of power sothat by shifting the belt on the pulleys the dryer cylinder may berotated at different speeds in the conventional manner.

By the gear arrangement shown the dryer cylinder I I is rotated in thesame direction but at a slower speed than the power shaft I9, and thisdifference in speed of rotation of cylinder and shaft makes for idealadaptability of the doctor reciprocation control means of the presentinvention but without absolute essentiality of such speed difference.

The illustrated doctor device comprises an elongated body member ofangle iron section, one

plate portion 24 of which carries the blade member 25. As conventionallyshown in Figs. 1 and 2, the attachment of the blade member 25 to thebody plate 24 is with a reinforcing strip 25. At the opposite ends ofthe body plate 24 are projecting, axially aligned, supporting bars 21,of round section. These projected bars ride on round-grooved rollers 28which are journalled in bearing elements 29 secured on supportingbrackets 30 that are attached to the adjacent main frame members H), asmore clearly shown in Fi 2.

As supported on the rollers 28 the doctor device is reciprocablelongitudinally of the dryer cylinder l0, and as the projected end-bars21 are rotatable as well as longitudinally movable on the groovedsupporting rollers 28, said bars serve as trunnion's whereby the doctordevice is rockable thereon. In this way the device is swingable aboutthe axis of the bars 21 in order to move the blade member 25 towards andaway from the dryer cylinder l, at will.

The relative position and distance of the axis of the supported end-bars21 of the doctor device from the dryer cylinder II, with thepreponderance of weight below the axis, is such that, normally, theouter edge portion of the blade 25 is maintained in contact with thecircumferential face of the cylinder. However, if it is desired to movethe blade 25 out of contact with the cylinder it is only necessary tooperate a cam 3| that is provided for the purpose.

As shown, the doctor device has a rigid downwardly extending tail-piece32 adjacent the lower end of which is the cam 3|. The cam 3| is normallyjust clear of the tailpiece 32, it being rotatably mounted in a bearingbracket 33 depending from the adjacent bracket member 30 and having anoperating handle 34 that hangs down from the bearing bracket 33 and thusholds the cam in a normally neutral position.

To disengage the doctor blade 25 from the dryer cylinder II the handle34 is swung upwardly to move the high portion of the cam against thetail-piece 32. This may be done either while the doctor device is atrest or during reciprocation thereof, as the tail-piece 32 is of awidth, commensurate with the length of stroke of the reciprocatingdoctor member, for the tail-piece to remain in contact with the cam 3|while the cam is set to tilt the blade 25 away from the dryer cylinder.

Any suitable motive element may be provided for operating the doctordevice. In the illustrative embodiment of the invention a conventionalcompressed air type of motor 35 is attached to the underside of thelower wing 38 of the rightangular body member of the doctor device (seeFig. 1). Suflice it to say that this type of motor has a reciprocatorypiston (not shown) the stem of which protrudes through and beyond theend of the body clinder and is attached at its outer end to a thrust-bar31 positioned on a supplemental angle bracket 38 that is mounted on theadjacent main bracket member 30 (see Fig. 2). By this provision andarrangement the reciprocation of the motor piston causes a correspondingmovement of the doctor device. Sufiice it to further state while thethrust-bar 31 is normally stationary and firmly supported during thereciprocatory operation of the doctor device, provision is made, as by aconventional slot-and-bolt mounting (see Fig. 1), for a compensatingrocking and lengthwise sliding movement of said bar on its support whenthe doctor device is rocked on its supporting end bars 21 to move theblade 25 into and out of contact with the dryer cylinder.

Compressed air for operating the motor 35 is supplied from the source(not shown) through a pipe 39 leading into a conventional unitaryassembly of an air filter 40, pressure regulator 4| and lubricator 42,which parts may be mounted stationarily on any convenient part of themachine frame, with a flexible hose 43 connecting the lubricator element42 to the intake of the motor 35 for supplying the compressed air and aproportionate amount of lubricant therewith to the motor.

All of the foregoing described parts of the paper making machine andappurtenances are conventional, and, per se, do not enter into thepresent invention other than incidentally in illustration of relativeassociation of the parts and elucidation in the specification andclaims.

For the purposes of the present invention the air supply pipe 33 isprovided with a. self-closing valve 44, conventionally indicated in Fig.2. Suflice it to say that, for example, this valve has a reciprocatorystem 45 attached to the core of a conventional solenoid 46 so that, whenthe magnet coil of the solenoid is energized, the stem 45 is therebyattracted and moved to open the valve 44 to supply the compressed air tothe motor 35.

The solenoid 45 is in an electrical circuit 4! from any suitable sourceof electrical energy, usually volt current supply. As diagrammaticallyillustrated the source is conventionally indicated as at supply 43, butthe same may be otherwise indicated. This circuit is normally brokenexcept during the time the dryer cylinder ll of the paper making machineis rotating and it includes a switch in cooperative relation to thedriving means of the dryer cylinder whereby to automatically close thecircu't when the cylinder begins to rotate and break the circuit whenrotation ceases.

The illustrated switch, designated generally by the numeral 49, isdirectly associated with the end of the power shaft I9 of the machine.As shown more clearly in Figs. 3 and 4, the switch unit comprises ahousing in which two interfiitting rotatable members 50, 5|, arelocated. The member 50 is cupped with a cylindrical collar portion andthe other member 5| is in the form of a plain cylindrical disk of suchdiameter that it fits peripherally rather snugly into the collar portionof the member 50 so that, by frictional contact between the adjacentcircular surfaces, the rotating of one member rotates the other memberunless held by some resistance or reversed by a force sufiicient toovercome the friction between the members.

The member 5| (the driver) has an axial stubshaft 52 journalled in abearing opening in the switch housing. The stub-shaft has a bifurcatedcross-head 53 fixed on its outer end. The parallel forks of thecross-head are located in the path of a radial driving arm 54 fixed onthe end of the power shaft l9. Thus, when the shaft I3 is rotated thedriving arm 54 engages one of the forks of the cross-head 53 and theswitch member 5| is thereby rotated in the same direction. At the sametime, rotation is imparted to the companion switch member 50 untilarrested as will now be described.

The rotatable switch member 53 carries on its periphery a longitudinallyextending contact arm 55 which is normally held in a neutral position bya. pair of opposed equalizer springs 56. In its neutral position thecontact arm 55 is disposed in spaced relation midway between two opposedpairs of circuit terminal contacts 51, 58, respectively. The contacts51, 58, are shown conventionally as spaced apart and insulated from theswitch housing, and the contact arm 55 is conventionally provided withspanner contacts 59, 60, on opposite sides thereof and insulated there'-from, whereby to engage and electrically connect a pair of the contacts51 or 58, according to which lateral direction the contact arm 55 ismoved.

For the purpose of illustrating the present invention as applied to amachine in which the working rotation of the cylinder or drum againstwhich the doctor device bears is in one direction, only one pair of theswitch contacts 51 are used as part of the solenoid circuit 41 asindicated by the pair of wires 41A and 41B of the diagram in Fig. 2 andalso as indicated in the views of the switch unit in Figs. 3 and 4.

When the switchmember 50 is arrested in its rotation by the engagementof the spanner contact 59 with the pair of terminal contacts 51 duringthe operation of the machine, the companion member 5| continues torotate with th power shaft l9. For this reason the lower portions of thetwo members 50, 5|, are immersed in a heavy oil contained in the housingas indicated at 6| in Fig. 4. The oil thus provided, not only lubricatesthe members 50, 5|, where the rubbing occurs between them, but theviscosity of the oil used causes a substantial dragging effect of therotating driver member 5| upon the companion member 50 which carries thecontact arm 55. Said member 50 is thus rotated between the limits ofapproximately 18 degrees and the contact arm 55 is thereby held with itsspanner contact 59 in steady contact with the pair of terminal contacts51 until such time that rotation of the driver member 5| is stopped.When rotation of the member 5| ceases, even though the driving arm 54 onthe power shaft |9 still be against one of the forks of the bifurcatedcross-head 53 and thus prevent rotation of the member 5| in thatdirection, the strength of the equalizer springs 58 is ample to forcerotation of the companion member 50 and thus instantly return thecontact arm 55 to its centralized neutral position between and out ofcontact with both pairs of circuit terminal contacts 51, 58.

Instantly, as the switch unit 49 operates to close the circuit 41, thesolenoid 45 becomes energized and thus automatically efiects the openingof the compressed air supply valve 44 and the doctor device is forthwithreciprocated. At approximately the same time, the dryer cylinder II hasstarted to rotate because of the ratio of its driving gears 6, 1 and I8and by virtue of which the power shaft IS in motion has made a certainnumber of revolutions sufiicient for the driven switch driver member 5|to have caused rotation of the companion switch member 50 and therebyeifected the closing of the solenoid circuit. Just as instantaneously,the solenoid circuit is broken when rotation of the power shaft l9ceases. Thus, the self-closing valve 44 immediately functions to shutoff the compressed air supply to the motor 35 so that operation 01' thedoctor device ceases substantially at the moment rotation of a normallyopen switch member arranged in re- 1 lation to the rotating means forsaid roll for closing upon rotation of the roll, and an electric circuitincluding the starting and stopping means for said doctor motive elementand said switch member, said electric circuit being connected to actuatesaid starting and stopping means to starting position when said switchmember is closed, whereby back and forth movement of said doctor isautomatically effected constantly during rotation of said roll at aspeed independent of the rotating speed of the roll and movement of saiddoctor is automatically stopped when rotation of said roll ceasesthereby avoiding scoring of said roll by said doctor.

2. In a paper making machine having a roll for conveying the paper weband means for rotating said roll, a doctor blade associated with saidroll, an air motor for moving said doctor back and forth transversely ofthe paper travel and in contact with said roll constantly duringrotation of the roll and at a speed independent of the rotating speed ofthe roll, an electrically actuated valve element for stopping andstarting said doctor motive element, said valve element being biased instopping position, a normally open switch member arranged in relation tothe rotating means for said roll for closing upon rotation REFERENCESCITED The following references are of record in the file of this patent:

' UNITED STATES PATENTS Number Name Date 2,300,908 Broughton Nov. 3,1942 1,644,917 Frossard et a1. Oct. 11, 1927 2,058,369 Taylor Oct. 20,1936 1,861,245 Smith May 31, 1932 1,482,167 Varley L Jan. 29, 19242,232,752 Wilson Feb. 25, 1941 1,618,146 Buel Feb. 15, 1927

